<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*标签选择器*/
        div{
            color:green;
        }
        /*类选择器*/
        .cls{
           color:red;
        }
        .box{
            width:100px;
            height:100px;
            background-color: cadetblue;
        }

    </style>
</head>
<body>
<div>我是div</div>
<div class="cls box">我是div</div>
<div>我是div</div>

<p>你是p</p>
<p>你是p</p>
<p>你是p</p>


<h3>任职要求</h3>
<ol>
    <li>实现阿是穴阿是穴</li>
</ol>
</body>
</html>